Keysight Technologies DSO-X 2014A, User Manual

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80 Keysight InfiniiVision 2000 X-Series Oscilloscopes User's Guide
4
Math Waveforms
• Offset — lets you set your own offset for the FFT. The offset value is in dB and
is represented by the center horizontal grid line of the display. See "To
adjust the math waveform scale and offset" on page 71.
• More FFT — displays the More FFT Settings Menu.
2 Press the More FFT softkey to display additional FFT settings.
• Window — selects a window to apply to your FFT input signal:
• Hanning — window for making accurate frequency measurements or for
resolving two frequencies that are close together.
• Flat Top — window for making accurate amplitude measurements of
frequency peaks.
• Rectangular — good frequency resolution and amplitude accuracy, but use
only where there will be no leakage effects. Use on self-windowing
waveforms such as pseudo-random noise, impulses, sine bursts, and
decaying sinusoids.
• Blackman Harris — window reduces time resolution compared to a
rectangular window, but improves the capacity to detect smaller impulses
due to lower secondary lobes.
• Vertical Units — lets you select Decibels or V RMS as the units for the FFT
vertical scale.
• Auto Setup — sets the frequency Span and Center to values that will cause
the entire available spectrum to be displayed. The maximum available
frequency is half the FFT sample rate, which is a function of the time per
division setting. The FFT resolution is the quotient of the sampling rate and
the number of FFT points (f
S
/N). The current FFT Resolution is displayed
above the softkeys.